Circuit-breaker.



l. NNTZIGER. H. CHAUVIN F. FONTAINE.

c mcun sREAxE-n. APPLICATIN FILED SEPT. 7. i916.

Z SHEETS-SHEET l.

Lan Kn friser' He'nnan Chan/vi n Felix Fonlfqine l. KNTZIGER. H. CHAUVIN & F. FONTAINE.

CIRCUIT. BREAKER.

APPLlcmon mtu SEPT. 1.1916.

Inven lofS L,

Patented Apr. 1; 1919.

2' SHEETS-SHEET 2.

' UNITED sTATEs PATENT oEEIoE.

l xn'rzrelm, Hman cmuvnv, man; mummia, .on LIEGE, BELGIUI CIRCUIT-nimma. l

1o au fwhomt'tm concern: A I

Be. 1t known t at we, JEA'N KNTZIGER, HERMAN CHAUVIN, and FLIXITOrITAnar -subjects of the Kingdom of Belgium,

residents of,Liege, Belgium, have invented certain and useful Improvements in Circuit- Breakers; and we do hereby declare the following to be a full, clear, and exact description of the invention, such 'as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings,

and to letters or figures of reference marked therein, which form a part of this specification.

The present invention relates to a circuitbreaking device for continuous or alternating current.

According to this invention' the decrease of tensile strength of a wire, dueto the heating effect of a current passing therethrough, is utilized to effect the rupture of an electric circuit. vThe wire is preferably arranged in th'e circuit'to be cont-rolled and is 4normally subjected to tension. `As the wire isv heated, its tensile strength diminishes and the tension thereon is ultimately suilcient to rupture the same and ez'ect the breaking of.

the circuit.

It is to' be noted that the working of such a circuit-breaker--is quite different from the working of apparatus in which fuses are employed. lThe wire` does notbecome warm under the normal conditions and the mechanical means stretching the wire is reguthe latter becomes warm, its tensile strength diminishes and at a determined temperature far below the melting point, the wire breaks and the circuit is consequently broken.

The desirable physical characteristics of the wire adapted to be traversed by the circuit to be broken, is found in standard steel wires used in .the electrical industry for4 rotor wire binding, and also in bronze wires having the following composition: copper 87%, tin 48.7% and zinc 4.3%.' Such a wire is a standard trade article in the metal industry. A Y

Specmcationof Letters I'atent.

from exterior influences.

Patented Apr. 1, 1919.

Appleman nieasep'tember 7,1916. semi mi. 118,915

` vExperiments have proved that when--the intensity of current passing through such a proportion to very small increase in the current; it is consequently possible to obtain in the working of the device a precision not attainable with fuse-devices. As the wire breaks at a temperature far below the melting-point the danger of the wire becoming melted is obviated. The 'metal of which the wire is made mustbe homogeneous, its ten- .sile strength must be near its limit of. elasticity and its elongation when breaking must be small. i

The wire may be covered by a Isuitable sheath to prevent dissipation of heat and to protect it-from exterior influences.

The wire may be traversed by the whole current or a portion ofthe current may be shunted therethrough. In the first case, the rupture of the wire directlv effects the interruption of the current; in the other case, the rupture of the wire is adapted to cause the opening of a switch through which the main current passes.

When a shunt is used, the wire breaks without any sparking or arcin'g, however high the voltage may be; it is consequently not necessary to increase the length of the wire in order to prevent arcing when high voltages are used. Identical wires may therefore be used in various apparatus intended for different voltages or different intensities of current. y

Then the wire is shunted, it is easy to obtain-as long a retardationin the working as mayv be required. It is therefore'only necessary to construct the shunt of a metal whereof theresistance varies according to the temperature, said shunt being covered by a sheath which prevents any transmission of heat and effectively protectsthe same In this way a circuit-breaker with retardedworking is obtained, that is to say a circuit-breaker in which the circuit is only broken after a current of predetermined intensity has been transmitted for a certain time. Such a circuit-breaker does not possess the inconveniences of other circuit-breakers with retarded working in which an electro-magnet device is utilized in -combination with relays, disengaging apparat-us, clock-work or other similar devices. It iste be noted that the 21,11@ wire 2o and blade 22. The knifei l26.- When the wire breaks,` the knifeblade 21 turns on its ivot and the nose 27 thereon actuates the rod 28 Iwhich inturn lifts the spring-pa'wl 26. The blade 22 is then allowed Vto turn under the action ofthe spring 24 and consequently interrupt the circuit.

In the embodiment illustrated in Fig. 4, the movable portion of the circuit-breaker comprises the two knife-blades 31 and 32 pivotally mounted respectively at 33 and 34 upon insulated brackets 35 and 36'ixed to i the plate' 37.

Theknife-blade 31, which is integral with the handle 38,' isbrought into contact -with the terminal 39' when it is pushed between the iexible jaws `40 connected to the said terminal'39. The knife-blade 32'is provided 'with brushes 41 adapted to contact with the blade 42 connected tothe terminal 43; this blade is connected at 44 to a spring 45 which .urges the 'blade to turn' on its pivot 34, so as to separate the brushes 41 andthe blade 42 The two 'knife-blades 31 and 32 are electrically connected together first by means of a shunt 46l of a metal the resistance of which varies according to the` temperature, and also by means 'of a small wire 47 which when traversed by a current` of increasing intensity causes 4the working of the apparatus.

'The shunt 46 is connected with the blades 31 and 32 by the terminals 48 and 49 and the flexible wires 50 and 51. When the wire 47 breaks underthe action of the spring 45, the blade 32 turns on its pivot 34, and the brushes 41 are quickly disengaged from the blade 42, so that the circuit is broken.

'The blades 32 and 42 may be provided with metal strips 52 and 52 between which the breaking sparknis produced.

When the apparatus is Ato'be opened by hand, it is only necessary to actuate the handle 38 after having pushed the rod 53 of said handle so as to disengage the -springpawl .54. 4The knife-blade 31 is then moved by the handle and the knife-blade 32 by the act-in ofthe spring 45.

4It is to be noted that in such a circuitbreaker the resetting is prevented, since if the apparatus is again closed after the broken wire' has been replaced, the circuit will be broken again if the overload in the circuit. .is still existing, even if the operator holds the handle 38 in the closed position.

It` is hardly necessary to mention that such an apparatus may be used for high tension or low tension currents. When high tension currents are'used, it is advantageous to send into the apparatus, inlieu of the high tension current, 'a low tension current obtained by means of a transformer; the movements of the parts of the low tension apparatus are then mechanically transmitted to a suitable device adapted to interru t the high tension current.

Ve claim:

1. In a circuit-breaker, the combination of an insulating tube closed by a metal bottom "plate connected with one end of the circuit to be broken, and by a ca a plate being adapted to move inside sai tube; of means for connecting said movable plate with the other end of the circuit to be broken, a Wire 'made of a metal having a lhigh tensile stren th and a limit of elasticity approximate y coincident with the breaking point, With little elongation when breaking, means for securing one of the ends of said wire to the said 'base late and the other end to. themovable p ate and a very strong spring tending to force the said plates apart.'

2. In a circuit-breaker, the combination of an insulating` tube closed by a metal -bottom plate connected with one end of the circuit to be broken, and by a cap, a plate being adapted to move inside said tu e: of means for connecting said movable plate with the other end of the circuit to be broken, a wire made of a metal having a high tensile strength and a limit of elasticity approximatel coincident withthe breaking point, with ittleA elongation 'when breaking, means for securing one of the ends of said wireto the s aid base plate and the other end to the movable plate, va rod secured to the movable `plate andpassing freely through the cap to indicate outside the position of thel movable 

